Thermally stabilized environmental system



Jan. 4, 1966 v. L. POTTER, JR, ETAL 3,227,208

THERMALLY STABILIZED ENVIRONMENTAL SYSTEM 2 Sheets-Sheet 1 Filed April 26, 1962 INVENTORSI VERNON L. POT 7' /?,J/-?. JOHN A. POTTER 4 ffamey.

Jan. 4, 1966 v. POTTER, JR., ETAL 3,227,203

THERMALLY STABILIZED ENVIRONMENTAL SYSTEM Filed April 26, 1962 I 2 Sheets-Sheet 2 9 I INVENTORS! VERA/0N L. POT TEE/R JOHN .4. POTTER, BY

Unite Stats 3,2212% THERMALLY STABILEZED ENVIRGNMENTAL SYdTEM Vernon L. Potter, In, Torrance, and John A. Potter,

Portuguese Bend, Calif., assignors to The Garrett Corporation, Los Angeles, Caiifl, a corporation of California Filled Apr. 26, 1962, Ser. No. 190,317 4 Claims. (Cl. 165-96) This invention relates to a thermally stabilized environmental system for an enclosure such as a completely enclosed protective suit.

When a person is exposed to a highly uncomfortable or uninhabitable environment, it is necessary to provide protection against noxious fumes and vapors that may be encountered. Such protection is normally provided by a protective suit that totally encloses the user. However, when a completely enclosed protective suit is utilized, it has been found that unless an adequate environmental system is provided for conditioning and ventilating the atmosphere within the suit, the user may be subjccted to physical discomfort which can result in fatigue, tension, and possible physical disability.

It is therefore an object of the present invention to alleviate or remove the above difliculties by providing an independent, self-contained, thermally controlled environmental system that may be utilized to supply the occupant of a completely enclosed protective suit With a constant flow of conditioned breathable fluid.

It is a further object of the invention to provide an environmental system of the aforementioned type that can be assembled and worn as a pack, which may be strapped on the users back and/or incorporated within his completely enclosed protective suit.

It is another object of the invention to provide an environmental system of the aforementioned type having means to cool its user when the protective suit is used in unusually high ambient temperatures and to warm its user when the protective suit is used in very cold environments.

It is still another object of the invention to provide an environmental system of the aforementioned type wherein the fluid within the protective suit is maintained at any predetermined temperature by an automatic thermal control operating in conjunction With a high temperature heat source and a low temperature source utilizing the cooling capabilities of cryogenic fluids.

It is a still further object of the invention to provide an environmental system of the aforementioned type wherein the fluid in the protective suit is maintained under pressure to retard or prevent noxious fumes or vapors from permeating into the suit.

Still another object of the invention is the provision of a heat exchanger having a heat source disposed to provide thermal energy to supplement the sensible and latent heats generated by the user of the protective suit when the temperature of the fluid within the suit drops below some predetermined level.

Other and further objects of the invention will be apparent from the disclosure in the following specification, appended claims and drawings, wherein:

FIG. 1 is a perspective view of a portable container for the environmental system supported inside the protective suit;

FIG. 2 is a perspective of the environmental system in the container with the cover of the container removed;

FIG. 3 is a schematic representation of the environ mental system shown in the container in FIG. 2;

FIG. 4 is an enlarged sectional view of the thermal control valve employed in FIG. 3; and

FIG. 5 is a longitudinal section through the heat exchanger taken on line 5-5 of FIG. 3.

3,227,208 Patented Jan. 4, 1966 Referring to FIG. 3 of the drawings, there is shown a schematic representation of an environmental system designed to provide a continuous flow of conditioned breathable fluid at a preselected temperature to a protective suit and helmet, as shown in phantom in FIG. 1. The suit and helmet form no part of the subject invention and may be of any type that totally encloses its occupant and aflords protection from hostile environments or excessively hot or cold atmospheres.

The environmental system is adapted to be assembled and contained within an independent, portable pack container to having an outer casing 11. In use the pack container 18 may be located and secured on the users back, utilizing a conventional shoulder harness and waist strap as shown in FIG. 1. When used in this manner both the pack container and the user are completely enclosed in the protective suit.

The environmental system includes a conventional double walled cryogenic storage vessel 13 having a duct 14 connected to the bottom thereof. The storage vessel is filled to a predetermined level with a supply of liquid air, liquid oxygen or any liquid, breathable fluid which is conveyed to the vessel through the duct 14 and a fill port 15 controlled by a check valve 16. A vent port 18 is connected to the top of the vessel and is provided with a bleed valve 19 to vent the gaseous fluid above the liquid fluid in the vessel to the atmosphere when the liquid fluid is conveyed to the vessel through the duct 14 and fill port i5.

A portion of the liquid fluid in the duct 14 is diverted through a duct 20 to a pressure buildup coil 21 where it is converted to a gaseous fluid by the absorption of heat. The gaseous fluid flows from coil 21 through duct 22, pressure closing valve 23 and pressure buildup valve 24 to the space 26 above the liquid fluid in the storage vessel 13 where the energy built up by the heat absorbed in the coil 21 is utilized to pressurize the liquid fluid in the vessel. With the pressure buildup valve 24 in the open position, the gaseous fluid continues to flow through duct 22 to the space 26 in vessel 13 until the pressure in space 26 reaches a preselected value sutficient to close valve 23. A relief valve 28 is provided in duct 22 to prevent the pressure in space 26 from exceeding a preselected value.

The preselected pressure maintained in the space 26 above the liquid fluid is adequate to force liquid fluid through the duct 14 to a vaporization coil 30 within a heat exchanger 31. The heat exchanger has an inlet passage 32 having a venturi shaped portion 33 for directing a flow of fluid in heat transfer relationship to the coil 5% to vaporize the liquid fluid therein, and a conditioned fluid outlet 34 connected to a flexible hose 35. A valve 36 is secured to the bottom of the heat exchanger 31 for draining the water and condensate from the exchanger.

Means are provided for controlling the temperature of the fluid in the heat exchanger inlet 32 and include a recirculating and thermal control valve, indicated generally at 38, having an outlet duct 39, a first passage 45 adapted to receive fluid from the protective suit, and a second passage 41 connected to the discharge 4-2 of a heat exchanger 43 having a high temperature heat source.

An ejector nozzle 45 is positioned in the duct 39 to induce fluid to flow through the passages 46 and 41. The nozzle 45 is joined to the outlet of the vaporization coil 39 by a conduit 46 having a flow initiator valve 47. As the vaporized or gaseous fluid issues from the nozzle 45 it mixes With the induced fluid flow from passages 40 and 41 and the fluid mixture is discharged through the heat exchanger inlet 32.

Pivotally disposed within the thermal control valve 38 at the junction of passages 46 and 41 48 that rotates about an axis 49 to proportion the fluid flow through the passages 40 and 41 in accordance with the temperature sensed by a thermal sensor unit 56 disposed in the passage 4%. The thermal sensor unit per se forms no part of the invention and may be of the usual commercial type having a material that expands and contracts in response to changes of temperature in the passage 40 to modulate a pin 51. As the pin 51 modulates it contacts a lever arm 52 to rotate it about an' axis 53. The lever arm 52 and the valve member 48 are hingedly connected at 54 so that linear actuation of the pin 51 produces rotary movement of the valve member 48.

The high temperature heat source in the heat exchanger 43 includes a sealed inner pressure vessel 57 containing a material 58 having the ability to supply large quantities of heat. In the present example the material 58 is lithium hydride and thermal energy storage input is accomplished by means of an electric heating element 59 having means (not shown) for connection with an electrical power source. A pressure sensing and indicating device 64) is aflixe-d to the pressure vessel 57 to allow constant monitoring of the state of the lithium hydride in the vessel.

Although lithium hydride and an electric heating element comprise the heat source in the present example, it is to be understood that other types of heat sources may be utilized in the inner pressure vessel 57. For example, the heat source may comprise a material capable of releasing large quantities of heat, for example, through an exothermic chemical reaction,.as in combustion, or through crystallization, as will be apparent to those skilled in the art. 7

In order to control thermal output, the inner vessel 57 is wrapped in insulating material 62 and the material is encased in a shield 63. Spaced from the shield 63 to form a passage 64 thereabout is a wall 65, The passage 64 has an inlet 66 for the admission of ambient fluid and an outlet 42 adapted to be connected to passage 41 of the thermal control valve 38, as noted above. To retain as much of the initial heat as possible, a second thermal barrier is provided comprising insulating material 68 held in place by a shield 69 disposed around the wall 65.

All the components of the environmental system are enclosed within the casing 11. The casing has a removable cover formed so asto allow access to the operating controls, thatis, the bleed valve 19, the pressure buildup valve 24, and the flow initiator valve 47, when the cover is in place.

In operation, the internal energy of the lithium hydride in the pressure vessel 57 is raised by permitting an electric current to flow in the heater element 59. The current is allowed to flow until the pressure sensitive device 60 indicates that the material 58 has reached a predetermined temperature level. The heat source at this time is in operable condition.

With the flow initiator valve 47 and the bleed valve 19 closed, the pressure buildup valve 24 is opened to permit gaseous fluid to flow from the pressure buildup coil 21 through the pressure closing valve 23, the pressure buildup valve 24 and the relief valve 28 to the space 26 in the storage vessel 13 to pressurize the system. When the pressure in the space 26 reaches the preselected value the valve 23 closes.

After the pack container is secured on the back of the wearer and the protective suit and helmet is donned, the flow initiator valve 47 is opened, the hose 35 is connected to a distribution system (not shown) within the suit, and the suit is closed. If desired, a predetermined portion of the fluid in the suit may be discarded through a suitable differential pressure controlled overload dump valve (not shown), to prevent an undesirable buildup of carbon dioxide in the suit.

With the flow initiator valve 47 open, the liquid fluid flows under pressure through the vaporization coil 30,

is a valve member r 4 absorbing heat from the fluid mixture flowing from the inlet pasasge 32 of the heat exchanger 31: As the liquid fluid passes through the coil 30 his converted to a gaseous fluid and energy is built up by the absorption of heat. The vaporized gaseous fluid passes from the coil 30 through duct 4-6 and the flow initiator valve 47 and issues from the ejector nozzle at substantially constant pressure, constant temperature and constant flow rate to induce fluid to flow from the protective suit through the passage 40, and from the high temperature heat source through the passage 41.

The fluid flowing through passages 40 and 41 combines with the gaseous fluid issuing from the ejector nozzle 45 and the combined fluid mixture is discharged through the duct 39 into the inlet 32, makes two passes through the heat exchanger 31 wherein it is cooled by the liquid fluid in the coil 36, and is ducted into the protective suit through the conditioning air outlet 34 and hose 35. Moisture removed from the fluid mixture during the cooling process is drained from the heat exchanger through the valve 36. The gaseous fluid issuing from the ejector nozzle 45 increases the pressure of the fluid mixture to compensate for suit pressure losses and to prevent the entrance of toxic fumes in the event of a tear or leak in the suit.

As the fluid is drawn from the protective suit through the passage 40, the thermal sensor unit modulates the pin 51 to position the valve member 43 in accordance with the temperature of the fluid in the passage. For example, if the temperature of the fluid flowing from the protective suit through passage 40 falls below a preselected levelthe pin 41 is retracted and the valve member iS moves in the clockwise direction to increase the flow of fluid through passages 41 and 64. Heat flowing from the material 58 in the pressure vessel 57 raises the temperature of the fluid in passage 64. The hot fluid is drawn from passage 64 through passage 41 to the inlet passage 32 of the heat exchanger where it mixes with the fluid flowing from the suit through passage 40 and the gaseous fluid issuing from the ejector nozzle 45 to increase the temperature of the fluid mixture flowing through the heat exchanger to the suit.

Conversely, if the temperature of'fluid flowing from the protective suit through passage 4%) rises above a preselected level the pin 51 is extended and the valve member 48 moves in the counter-clockwise direction to decrease the flow of hot fluid through passages 41 and 64. This, in turn, decreases the temperature of the fluid mixture flowing through the heat exchanger to the suit. Modulation 'of the pin 51 continues until a balance is achieved between the thermal losses to ambient and input from the heat sink. While the invention is described as utilized in an environmental system for a completely enclosed protective suit, it is to be understood that its utility is not limited' thereto since it may be utilized in other enclosures, such as tanks, compartments and many other applications, as will be apparent to those skilled in the art.

We claim: a -1. An environmental system for an enclosure, comprising: e

a source of liquid breathable fluid; heat exchange means having a vaporization coil, an

inlet passage disposed to convey fluid in heat transfer relationship with said vaporization coil, and a conditioned air outlet communicating with the enejector means disposed between both of said first and second passages and said vaporization coil of said heat exchange means upstream of said vaporization coil;

conduit means for conducting gaseous fluid from said vaporization coil to said ejector means, the ejector means being disposed so that the gaseous fluid issuing therefrom induces fluid to flow through said first and second passages into said inlet passage and mix with said gaseous fluid whereby the combined fluid mixture is circulated over said vaporization coil and back to the enclosure;

and means for proportioning the fluid flow through said first and second passages in response to the temp-erature of the fluid in said first passage.

2. An environmental system for an enclosure, comprising:

a source of liquid breathable fluid;

a heat exchanger having a first pass comprising a vaporization coil;

duct means connecting said source of liquid breathable fluid with said vaporization coil;

means for circulating fluid from the enclosure through a second pass in said heat exchanger in heat transfer relationship with said vaporization coil and back to the enclosure; a high temperature heat source having means for introducing heated fluid into said circulating means; ejector means disposed in said circulating means upstream of said heat exchanger;

conduit means for conducting gaseous fluid from said vaporization coil to said ejector means, the ejector means being disposed so that the gaseous fluid issuing therefrom will aspirate fluid from the enclosure and from the high temperature heat source into said circulating means whereby the combined mixture of gaseous fluid from the ejector means, fluid from the enclosure, and fluid from the high temperature heat source will be circulated over the vaporization coil and back to the enclosure;

and means responsive to the temperature of the fluid in the enclosure for modulating the flow of heated fluid into said circulating means.

3. An environmental system for an enclosure according to claim 1 wherein said source of liquid breathable fluid comprises a container for storing and supplying liquid breathable fluid, and means for pressurizing said container.

4. An environmental system for an enclosure according to claim 1 wherein said high temperature heat source comprises a chamber, material in the chamber capable of storing heat, and means for supplying heat to said material.

References Cited by the Examiner UNITED STATES PATENTS ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner. 

1. AN ENVIRONMENTAL SYSTEM FOR AN ENCLOSURE, COMPRISING: A SOURCE OF LIQUID BREATHABLE FLUID; HEAT EXCHANGE MEANS HAVING A VAPORIZATION COIL, AN INLET PASSAGE DISPOSED TO CONVEY FLUID IN HEAT TRANSFER RELATIONSHIP WITH SAID VAPORIZATION COIL, AND A CONDITIONED AIR OUTLET COMMUNICATING WITH THE ENCLOSURE; MEANS FOR CONVEYING LIQUID FLUID FLOW SAID SOURCE TO SAID VAPORIZATION COIL WHEREIN THE LIQUID FLUID IS CONVERTED TO A GASEOUS FLUID; A DUCT COMMUNICATING WITH SAID INLET PASSAGE; A FIRST PASSAGE FOR CONDUCTING FLUID FROM THE ENCLOSURE TO SAID DUCT; A HIGH TEMPERATURE HEAT SOURCE; A SECOND PASSAGE IN HEAT TRANSFER RELATIONSHIP WITH SAID HEAT SOURCE FOR CONVEYING HEATED FLUID TO SAID DUCT; EJECTOR MEANS DISPOSED BETWEEN BOTH OF SAID FIRST AND SECOND PASSAGES AND SAID VAPORIZATION COIL OF SAID 